Error MSB3645: .NET Framework v3.5 Service Pack 1 was not found. In order to target ".NETFramework,Version=v3.5", .NET Framework v3.5 Service Pack 1 or later must be installed. (MSB3645) (Assembly-CSharp-firstpass)

The monodevelop is not letting me build the project and keeps on giving this error:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(5,5): Error MSB3645: .NET Framework v3.5 Service Pack 1 was not found. In order to target ".NETFramework,Version=v3.5", .NET Framework v3.5 Service Pack 1 or later must be installed. (MSB3645) (Assembly-CSharp-firstpass)

However I have it installed on my Windows 10. Any help to set it up as a root path for monodevelop to catch and stop throwing this error. Plus I get this warning:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets(5,5): Warning MSB3644: The reference assemblies for framework ".NETFramework,Version=v3.5" were not found. To resolve this, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framework for which you have the SDK or Targeting Pack installed. Note that assemblies will be resolved from the Global Assembly Cache (GAC) and will be used in place of reference assemblies. Therefore your assembly may not be correctly targeted for the framework you intend. (MSB3644) (Assembly-CSharp-firstpass)